*/
#include "includes.h"
-RCSID("$OpenBSD: dh.c,v 1.11 2001/03/29 21:17:39 markus Exp $");
+RCSID("$OpenBSD: dh.c,v 1.31 2004/08/04 10:37:52 djm Exp $");
#include "xmalloc.h"
#include "log.h"
#include "misc.h"
-int
+static int
parse_prime(int linenum, char *line, struct dhgroup *dhg)
{
char *cp, *arg;
/* Ignore leading whitespace */
if (*arg == '\0')
arg = strdelim(&cp);
- if (!*arg || *arg == '#')
+ if (!arg || !*arg || *arg == '#')
return 0;
/* time */
if (cp != NULL || *prime == '\0')
goto fail;
- dhg->g = BN_new();
- dhg->p = BN_new();
- if (BN_hex2bn(&dhg->g, gen) < 0)
+ if ((dhg->g = BN_new()) == NULL)
+ fatal("parse_prime: BN_new failed");
+ if ((dhg->p = BN_new()) == NULL)
+ fatal("parse_prime: BN_new failed");
+ if (BN_hex2bn(&dhg->g, gen) == 0)
goto failclean;
- if (BN_hex2bn(&dhg->p, prime) < 0)
+ if (BN_hex2bn(&dhg->p, prime) == 0)
goto failclean;
if (BN_num_bits(dhg->p) != dhg->size)
goto failclean;
+ if (BN_is_zero(dhg->g) || BN_is_one(dhg->g))
+ goto failclean;
+
return (1);
failclean:
- BN_free(dhg->g);
- BN_free(dhg->p);
+ BN_clear_free(dhg->g);
+ BN_clear_free(dhg->p);
fail:
error("Bad prime description in line %d", linenum);
return (0);
choose_dh(int min, int wantbits, int max)
{
FILE *f;
- char line[1024];
+ char line[4096];
int best, bestcount, which;
int linenum;
struct dhgroup dhg;
- f = fopen(_PATH_DH_PRIMES, "r");
- if (!f) {
- log("WARNING: %s does not exist, using old prime", _PATH_DH_PRIMES);
- return (dh_new_group1());
+ if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL &&
+ (f = fopen(_PATH_DH_PRIMES, "r")) == NULL) {
+ logit("WARNING: %s does not exist, using fixed modulus",
+ _PATH_DH_MODULI);
+ return (dh_new_group14());
}
linenum = 0;
linenum++;
if (!parse_prime(linenum, line, &dhg))
continue;
- BN_free(dhg.g);
- BN_free(dhg.p);
+ BN_clear_free(dhg.g);
+ BN_clear_free(dhg.p);
if (dhg.size > max || dhg.size < min)
continue;
if (dhg.size == best)
bestcount++;
}
- fclose (f);
+ rewind(f);
if (bestcount == 0) {
- log("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
- return (NULL);
- }
-
- f = fopen(_PATH_DH_PRIMES, "r");
- if (!f) {
- fatal("WARNING: %s disappeared, giving up", _PATH_DH_PRIMES);
+ fclose(f);
+ logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
+ return (dh_new_group14());
}
linenum = 0;
while (fgets(line, sizeof(line), f)) {
if (!parse_prime(linenum, line, &dhg))
continue;
- if (dhg.size > max || dhg.size < min)
- continue;
- if (dhg.size != best)
- continue;
- if (linenum++ != which) {
- BN_free(dhg.g);
- BN_free(dhg.p);
+ if ((dhg.size > max || dhg.size < min) ||
+ dhg.size != best ||
+ linenum++ != which) {
+ BN_clear_free(dhg.g);
+ BN_clear_free(dhg.p);
continue;
}
break;
}
fclose(f);
+ if (linenum != which+1)
+ fatal("WARNING: line %d disappeared in %s, giving up",
+ which, _PATH_DH_PRIMES);
return (dh_new_group(dhg.g, dhg.p));
}
-/* diffie-hellman-group1-sha1 */
+/* diffie-hellman-groupN-sha1 */
int
dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
int bits_set = 0;
if (dh_pub->neg) {
- log("invalid public DH value: negativ");
+ logit("invalid public DH value: negativ");
return 0;
}
for (i = 0; i <= n; i++)
if (BN_is_bit_set(dh_pub, i))
bits_set++;
- debug("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
+ debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
/* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1))
return 1;
- log("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
+ logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
return 0;
}
void
dh_gen_key(DH *dh, int need)
{
- int i, bits_set = 0, tries = 0;
+ int i, bits_set, tries = 0;
if (dh->p == NULL)
fatal("dh_gen_key: dh->p == NULL");
- if (2*need >= BN_num_bits(dh->p))
+ if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
fatal("dh_gen_key: group too small: %d (2*need %d)",
BN_num_bits(dh->p), 2*need);
do {
if (dh->priv_key != NULL)
- BN_free(dh->priv_key);
- dh->priv_key = BN_new();
- if (dh->priv_key == NULL)
+ BN_clear_free(dh->priv_key);
+ if ((dh->priv_key = BN_new()) == NULL)
fatal("dh_gen_key: BN_new failed");
/* generate a 2*need bits random private exponent */
if (!BN_rand(dh->priv_key, 2*need, 0, 0))
fatal("dh_gen_key: BN_rand failed");
if (DH_generate_key(dh) == 0)
fatal("DH_generate_key");
- for (i = 0; i <= BN_num_bits(dh->priv_key); i++)
+ for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
if (BN_is_bit_set(dh->priv_key, i))
bits_set++;
- debug("dh_gen_key: priv key bits set: %d/%d",
+ debug2("dh_gen_key: priv key bits set: %d/%d",
bits_set, BN_num_bits(dh->priv_key));
if (tries++ > 10)
fatal("dh_gen_key: too many bad keys: giving up");
dh_new_group_asc(const char *gen, const char *modulus)
{
DH *dh;
- int ret;
- dh = DH_new();
- if (dh == NULL)
- fatal("DH_new");
+ if ((dh = DH_new()) == NULL)
+ fatal("dh_new_group_asc: DH_new");
- if ((ret = BN_hex2bn(&dh->p, modulus)) < 0)
+ if (BN_hex2bn(&dh->p, modulus) == 0)
fatal("BN_hex2bn p");
- if ((ret = BN_hex2bn(&dh->g, gen)) < 0)
+ if (BN_hex2bn(&dh->g, gen) == 0)
fatal("BN_hex2bn g");
return (dh);
{
DH *dh;
- dh = DH_new();
- if (dh == NULL)
- fatal("DH_new");
+ if ((dh = DH_new()) == NULL)
+ fatal("dh_new_group: DH_new");
dh->p = modulus;
dh->g = gen;
return (dh_new_group_asc(gen, group1));
}
+
+DH *
+dh_new_group14(void)
+{
+ static char *gen = "2", *group14 =
+ "FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
+ "29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
+ "EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
+ "E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
+ "EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
+ "C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
+ "83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
+ "670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
+ "E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
+ "DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
+ "15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
+
+ return (dh_new_group_asc(gen, group14));
+}
+
+/*
+ * Estimates the group order for a Diffie-Hellman group that has an
+ * attack complexity approximately the same as O(2**bits). Estimate
+ * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
+ */
+
+int
+dh_estimate(int bits)
+{
+
+ if (bits <= 128)
+ return (1024); /* O(2**86) */
+ if (bits <= 192)
+ return (2048); /* O(2**116) */
+ return (4096); /* O(2**156) */
+}
andersk / openssh.git / blobdiff